Link to my Flickr album below. Some nebs and galaxies shot with modded Canon 650d at ISO800 with single 30 and 60 second exposures then adjusted in Astrotoaster, and the saved tif's then tweaked a tad more in Photo Gallery out there in the field while observing. Some show the signs of light reflections within the OTA as the site is a townhouse complex in the green zone of Clermont. The Eastern side of where I setup has a security light which shone up the OTA while it was pointing to any Eastern targets, and the northern stuff is over the township. Still for EAA that sort of aberation doesn't bother me. I should have adjusted it out but didnt bother. Sorry.
Thanks Chris. I have noticed a BIG diff between ISO800 and ISO1600 noise with my 650d. I studied the graphs on the sensorgen website and I have to be missing something regarding how it works (perhaps re-reading some of astrojedi's CN posts on the subject will give me the answer). Because sensorgen graphs and tables tell me the noise at iso6400 is less than at 1600 but I see huge grain at 6400 and much less at 1600. Then the graphs say there isn't much diff between 1600 and 800 but thats not what I see either. I reckon twice the grain at 1600 compared to 800.
There's a guy in the astro club who pretty much takes all his AP at iso400 and sometimes iso200, and then 5, 10 or even 20 minute exposures. Some of his single frames are stunning. It will prob be what I try first when I (eventually) get to guide ... iso400 with 5 minute exposures stacking 4 or 9 shots.